Systems and procedures are proposed for the detoxification of exhaust gas coupled with low fuel consumption which bring into play, in the case of the Otto motor, a weak mixture in rotation, in which, by means of this rotation the mixture rapidly reaches the spark plug thus ensuring better ignition and proper combustion. Very weak mixtures with a composition of Lambda 1.3 or less are therefore necessary so that not only the hydro carbons and carbon monoxide but also nitrogen content of the exhaust are very low.
A proposal from Ford and others is that, in the area of the inlet valves, by means of swirl-creating fittings, a spiral flow is created which continues in the combustion chamber up to the point of ignition. In the case of the continually-changing operating conditions of revolutions and performance, this system does not ensure correct ignition because the rotation cannot definitely be maintained in the compression cycle to the point of ignition and possibly breaks down before then so that the swirl is not maintained until the point of ignition.
As is known in DE 27 51 993 11, the "squish" space between the piston head and the corresponding wall of the cylinder head is so formed that near the top dead centre position of the piston at least one "squish" space flow is created in parallel to one wall of the combustion chamber so that this "squish" space flow in conjunction with the guide means arranged inside the combustion chamber results in a rotational flow. The spark plug is fitted in the area of the rotational flow so that even a very weak air-fuel mixture is enough for ignition.